Hello, I'm working on 1995 Supermax TC-2 cnc lathe. I recently purchased this machine after it has been sitting for around 5 years and the previous owner working on it on and off trying to repair it. It has Mitsubishi Meldas L3 control which I've been getting used to. After repairing few things and getting parameters set correctly I'm doing test parts to see how the lathe performs and ironing out post processor.
The issue I ran into has to do with surface finish on the arc. I'm cutting a part out of 6061 which is short piece of tube ~0.75" long 2.5" o.d. 2"i.d. and has a ball nose end. I'm roughing with CNMG432 for AL and finishing with [FONT=arial, sans-serif]CCGT 32.51 for AL. The finish pass is 0.01" DOC and 0.0015" IPR. The finish looks good on the straight portion of the tool-path but when the radius is cut the it is not smooth and has steps.[/FONT]
[FONT=arial, sans-serif]I checked the G-code and it is commanding G03 X.. Y.. R.. so I know it is not cutting in segments. When I first noticed this problem I thought that the CNMG432 was part of the cause but going to CCGT 32.51 still produces similar profile on the radius and improved finish on the straight section.[/FONT]
[FONT=arial, sans-serif]I think this might be a problem with the machine it self. I decided to take a closer look at the part under the microscope and see if I can learn anything. Below are few pictures from the microscope:
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It seems to me that the problem is interpolating both axis simultaneously. I've tried different inserts and different feeds but the profile is coming out very similar which makes me think it is not the control but rather mechanical issue.
In the first picture I noticed a pattern ~0.2mm (~0.01") spacing along the Z-axis which continues onto the radius.
Please advise me on what tests I can do to narrow things down. In writing this I realized that I need to make a finish facing cut and see if there are any patterns there.
The pitch of the screws doesn't seem to coinciding with the ridges that I'm seeing maybe it is a bad bearing somewhere.
Any help and suggestions are highly appreciated.
P.S. now time to read up on how to fit a test scales to see what the axis are doing.
The issue I ran into has to do with surface finish on the arc. I'm cutting a part out of 6061 which is short piece of tube ~0.75" long 2.5" o.d. 2"i.d. and has a ball nose end. I'm roughing with CNMG432 for AL and finishing with [FONT=arial, sans-serif]CCGT 32.51 for AL. The finish pass is 0.01" DOC and 0.0015" IPR. The finish looks good on the straight portion of the tool-path but when the radius is cut the it is not smooth and has steps.[/FONT]
[FONT=arial, sans-serif]I checked the G-code and it is commanding G03 X.. Y.. R.. so I know it is not cutting in segments. When I first noticed this problem I thought that the CNMG432 was part of the cause but going to CCGT 32.51 still produces similar profile on the radius and improved finish on the straight section.[/FONT]
[FONT=arial, sans-serif]I think this might be a problem with the machine it self. I decided to take a closer look at the part under the microscope and see if I can learn anything. Below are few pictures from the microscope:
[/FONT]
It seems to me that the problem is interpolating both axis simultaneously. I've tried different inserts and different feeds but the profile is coming out very similar which makes me think it is not the control but rather mechanical issue.
In the first picture I noticed a pattern ~0.2mm (~0.01") spacing along the Z-axis which continues onto the radius.
Please advise me on what tests I can do to narrow things down. In writing this I realized that I need to make a finish facing cut and see if there are any patterns there.
The pitch of the screws doesn't seem to coinciding with the ridges that I'm seeing maybe it is a bad bearing somewhere.
Any help and suggestions are highly appreciated.
P.S. now time to read up on how to fit a test scales to see what the axis are doing.